Step 1: Divide the number into separate digits:
55002 => 5 5 0 0 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 5 = 0
5 to 0 = 5
0 to 0 = 0
0 to 2 = 2
2 to 5 = 3
Step 3: Combine the filters to a string:
0 5 0 2 3 = 05023